🐛 [RUMF-1449] fix Zone support when __symbol__ is missing

[BenoitZugmeyer]

Motivation

We observed that some website define a Zone global variable unrelated to Zone.js, and this variable doesn't have a __symbol__ method, so it crashes the SDK.

Related: angular/zone.js#434

Changes

Check for the __symbol__ method before using it.

Testing

• Local
• Staging
• Unit
• End to end

---

I have gone over the contributing documentation.

[codecov-commenter]

Codecov Report

Merging #1872 (2dc5881) into main (d1b1a42) will decrease coverage by 0.07%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #1872      +/-   ##
==========================================
- Coverage   93.20%   93.12%   -0.08%     
==========================================
  Files         137      137              
  Lines        5165     5165              
  Branches     1153     1153              
==========================================
- Hits         4814     4810       -4     
- Misses        351      355       +4     

Impacted Files	Coverage Δ
packages/core/src/tools/getZoneJsOriginalValue.ts	100.00% <100.00%> (ø)
...rum-core/src/domain/contexts/foregroundContexts.ts	90.76% <0.00%> (-6.16%)	⬇️

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